Comparison Stark RH 850 Profi vs Dnipro-M RH-98

Rated power consumed by the rotary hammer during operation. Usually, the maximum power consumption in normal operation is taken as the nominal power.

In general, the higher this indicator, the heavier and more performant the rotary hammer is, the more advanced its performance usually turns out to be. On the other hand, the electricity consumption of such tools is high. In addition, note that with the same power consumption, the actual set of individual characteristics for different tools may be different. For example, frequency and impact energy are inversely related, and for the same power input, higher frequency usually means less individual impact energy. So, according to this parameter, it is worth evaluating only the overall level of the instrument; for accurate selection for specific tasks, you need to pay attention to more specific characteristics.

Also note that power consumption data can be useful for some tasks related to catering — for example, if a construction site is powered by an autonomous generator and you need to estimate the load on this energy source.

The energy transmitted by the perforator to the material being processed upon impact; the higher this indicator, the stronger and more powerful each individual blow.

First of all, we recall that the energy of impacts is directly related to their frequency: an increase in frequency leads to a decrease in energy. Therefore, for models where the number of strokes can be adjusted, this paragraph usually gives the maximum energy achieved at the minimum speed of operation.

In general, higher impact energy improves efficiency when working with hard, stubborn materials, but requires more motor power (especially if it has to be combined with a high frequency). Therefore, it is worth choosing according to this parameter, taking into account specific tasks. So, for occasional use in everyday life, an energy of 2 J or less is enough, for home repair work of medium intensity, at least 3 J is desirable; a power of 4 J or more is already considered high; and in some industrial-grade perforators, this figure can reach 30 J.

The number of beats per minute provided by the punch. For models in which the beat frequency can be adjusted, this item indicates the entire adjustment range, for example "1600 — 3000".

High impact frequency, on the one hand, increases the productivity of the tool and can significantly reduce the time required for work. On the other hand, with the same engine power, an increase in the number of strokes per minute leads to a decrease in the energy of each stroke. Therefore, among heavy performant devices, a low frequency is often found — up to 2500 beats / min and even lower. And the ability to adjust the frequency of impacts allows you to adjust the hammer to the specific situation, depending on what is more important — productivity or the ability to cope with hard, stubborn material. For example, for old crumbling brickwork, you can set the speed higher, and for working with stone or dense concrete, it is better to reduce the frequency of impacts by directing engine power to increase the energy of each impact.

Summing up, we can say this: when choosing a perforator, you should focus on both the number of strokes and the impact energy. Detailed recommendations on this subject for specific situations can be found in special sources.

The speed of rotation of the working equipment provided by the rotary hammer. Usually, this indicates the speed at idle, without load; rated load speeds can be further specified in the characteristics (see below), but this is rare, and this parameter is still considered the main characteristic. It is also worth mentioning that in the presence of a speed controller (see "Functions"), the maximum speed value is given here.

When working in the main mode — drilling with impact — the rotation of the equipment is used mainly to remove waste from the hole, and the revolutions here are of no fundamental importance (they can be very low). Therefore, it is worth paying attention to this indicator mainly in cases where the rotary hammer is planned to be often used for conventional drilling, without impact. And here it is worth proceeding from the fact that high speeds increase productivity and contribute to accuracy when working with some materials, but reduce torque (compared to tools with the same engine power). So for heavy work with hard, stubborn materials, relatively "slow" tools are usually better suited.

Note also that drilling is not the main task of rotary hammers; therefore, their rotation speeds are noticeably lower than those of the same drills. On the other hand, in this case, low speeds are often compensated by powerful engines and high torque, which makes it possible to effectively drill...holes of a fairly large diameter, including using crowns.

— Soft start. A function that provides a smooth spin-up of the tool motor, with relatively little acceleration. This is achieved by limiting the starting current. Without such a limit, the current drawn by the motor at the time of starting can be quite high, causing the motor to start very abruptly, which increases the risk of letting go of the tool. In addition, current surges can lead to overloads in the network used for power. Soft start allows you to eliminate these phenomena to some extent. Note that it only applies to mains powered models.

— Speed controller. Electronic limiter for the maximum speed of the tool attachment. This is implemented using a rotary switch on the tool body, turning it clockwise increases the maximum allowable speed, against — reduces it, which allows you to take into account the characteristics of the materials that need to be drilled or gouged.

— Maintain momentum. The presence of an electronic adjustment system that automatically adjusts the rotation speed depending on the diameter of the working tool and the type of material. At the same time, the regulator maintains a constant speed regardless of the load — by changing the power supplied to the tool. Automatic adjustment increases the quality of processing and productivity, and also increases the life of both the working tool and the hammer itself, ensuring optima...l operation.

— Soft blow(economy mode). A special mode of operation in which the impact energy and rotational speed provided by the rotary hammer are reduced. This affects two things: firstly, the tool acts less intensively on the material being processed, and secondly, wear and energy consumption are reduced. The first feature will be relevant when processing fragile materials that can be damaged by too powerful chiselling; the second — when working with soft materials, which lend themselves well to even not very strong impact.

— Anti-vibration system. The system for suppressing vibrations transmitted from the operating unit to the operator. Strong vibrations impair the accuracy of work, and also lead to rapid fatigue; vibration protection reduces these effects. It is used mainly in expensive professional models designed for long-term operation.

— Safety clutch. Mechanical safety system that protects the hammer from breakage, and the operator from injury in case of jamming of the working tool in the material. When this happens in the drilling mode, the engine experiences critical loads that can very quickly disable it, and when chiseling, the hammer itself also starts to move, transmitting vibration to the operator’s hands. The safety clutch is set to a certain load level; when it is exceeded, it is destroyed, breaking the connection between the working tool and the perforator mechanisms.

— Power button lock. The ability to block the power button in the off and/or on state. In the first case, the lock provides protection against accidental pressing, and can also play the role of child protection — the lock button is usually quite tight, and a curious little child will not be able to press it. The second option is useful if you need to work for a long time without a break, and it is inconvenient to keep the power button pressed all the time.

— Brushless motor. The presence of a brushless (brushless) motor in an electric tool. Such motors are noticeably superior to traditional collector motors in terms of efficiency, which can significantly reduce energy consumption without sacrificing power; this is especially important for cordless tools (see "Power Source"), where this feature is predominantly found. In addition, brushless motors are quieter and produce virtually no sparks during operation, making them perfect for working in high fire hazard environments. Their main disadvantages are traditional — the complexity of the design and high price.

— Backlight. The perforator has its own lamp that illuminates the work area. This feature is useful if there is little natural light, and there is no way to install artificial light — for example, when working in cramped conditions.

— Reverse. The reverse function allows you to rotate the working tool of the rotary hammer in the opposite direction. This can be useful, for example, to release a drill stuck in the material.

— Synchronization with a smartphone. The ability to connect the instrument to a smartphone or other gadget (such as a tablet) via Wi-Fi or Bluetooth. Such a connection is usually used to adjust operating parameters such as speed or torque; doing this through a mobile application is often more convenient than through the controls on the instrument itself. And some models with this function also allow you to set password access: the tool simply will not respond to the start button until the correct password is entered on the control gadget.

— Built-in spirit level. Built-in device to control the angle at which the tool is located to the horizon. As in ordinary levels, the role of the scale in such devices is played by a sealed flask with marks applied to it, containing a brightly coloured liquid and an air spirit. By the position of this spirit relative to the marks, the position of the entire tool is determined — namely, its correspondence to the vertical, horizontal, or pre-set tilt angle (the latter option, however, is almost never found in the built-in levels). At the same time, purely hand tools usually provide a single-axis level that reacts only to deviation from the horizontal forward or backward, and models with the ability to mount on a rack (see below) can also have a circular level that controls compliance with the vertical and determines deviations from it in any direction.

— Carbon brush replacement indicator. The presence of a special indicator in the design of the perforator, signaling the need to replace the carbon brushes. Carbon brushes are located in the electric motor and are the most worn part of it, because. subject to constant friction during operation. When the brushes are worn beyond a critical level, the engine power drops, it starts to work intermittently, which can lead to unpleasant consequences up to tool breakage or even injury. And replacing the worn brushes themselves is much cheaper than changing the entire electric motor or even the entire tool.

— Additional handle. The presence of an additional front handle on the hammer drill, usually located at the base of the chuck. This handle can be non-removable or removable, rigidly fixed or movable. Holding two handles with two hands is much more convenient than holding one and the body, as it allows for optimal distribution of the load on the hands; this is especially important during long-term work and processing of “heavy” materials.

— Depth gauge. A device that allows you to make holes of a strictly defined depth in one go, without constant measurements and without the risk of drilling deeper than necessary. Usually looks like a rod fixed to the body of the hammer drill parallel to the working tool. When used, this rod extends to such a length that when the desired depth is reached, it rests against the surface of the material being processed, preventing the drill from moving further.

— Chisel. Complete attachment for impact work with a hammer drill in the manner of chasing, leveling hard surfaces, chipping tiles, bricks, concrete, etc. Different types of chisels are produced for different tasks — flat, blade, groove, crushing peaks with a sharp tip.

— Boring bit. The presence of Boring bit in the delivery set of tool designed for processing various hard materials by drilling with impact. Buy...ing such a set eliminates the need to look for a drill separately, but the characteristics of the complete attachment must be clarified before purchasing, since they may not meet the buyer's requirements.

— Charger. The presence of a charging unit in the kit allows you to charge batteries. Accordingly, for models with batteries, this accessory is necessary to power the battery. However, there are models without a charger. And hammer drills with it can differ in the model of the charger, the name of which will allow you to learn more about its characteristics and, if necessary or as needed (breakdown), buy a similar one.

— Case included. The delivery set includes a special case that facilitates storage and transportation: it provides protection from impacts and adverse conditions (moisture, frost), is equipped with a special handle for carrying, in addition, in the case, along with the hammer drill itself, a set of working tools, replacement cartridges, etc. can be placed.

— Dust collector. The hammer drill comes with a special dust collector. As the name suggests, it is designed to collect dust generated during operation, which could otherwise cause significant inconvenience. It usually looks like a bag or container attached to the body; it can be either replaceable (thrown away with the collected garbage) or permanent. The dust collector slightly increases the weight and dimensions of the hammer drill, but it can be removed if necessary.

Power cord length for mains powered drills (see above). The longer the cord, the farther from the outlet you can use the unit and the less it depends on the location of the outlets.

The weight of a fully assembled rotary hammer (in the case of battery power, with a standard battery installed). Unlike many other types of equipment, in the case of rotary hammers, light weight is far from always an advantage. So, heavy models are better suited for professional use — they are less prone to vibrations and, usually, are stronger, which is important when working with difficult-to-cut materials for a long time. But for small, simple works of short duration, a lot of weight is not required, and in this case, light models are useful, which do not require significant effort to hold on weight.